Little Toby wants $350 for a new video game system, and has decided to save up some of his monthly allowance to do so. The first month he puts $4.32 into his piggy bank, and each month after that he puts an amount in his piggy bank that is $0.52 more than the last month's deposit.
If after 15 months Toby has enough money to buy his game system, how many dollars did he have in his piggy bank already when he started saving?